Train-controlling means by light rays



June H, E9290 w. BASELER TRAIN CONTROLLING MEANS BY LIGHT RAYS Filed Feb. 12, 1927 2 Sheets-Sheet zhwmlizylwy TRAIN CONTROLLING MEANS BY LIGHT RAYS Filed Feb. 12, 1927 z Sheets-Sheet 2 Patented June 18, 1929.

UNITED STATES 1,717,152 PATENT OFFICE.

WOLFGANG BKSELER, OF MUNICH, GERMANY, ASSIGNOR TO LORENZ-ZEISS-ZUGSICHE- 7 RUNGS G. M. B. H., 015 BERLIN-TEMPLEHOF, GERMANY.

TRAIN-CONTROLLING MEANS BY LIGHT RAYS.

Application filed February 12, 1927, Serial No. 167,759, and in Germany February 16, 1926.

This invention relates to an apparatus for the automatic control of trains by means of light rays and has more particularly for its object to provide a train control system for automatically stopping a locomotive of a railroad train in case it is passing a block signal which has been set against such passage of the train by a nearby rail signal station, under danger conditions, or for producing only an optical or acoustlc alarm signal on the locomotive in the event of the engine mans disregarding a danger stop signal.

Another object of my invention is to provide means selectively responsive with respect to different points of the track in order to produce different effects at such points, such as e. g. to sound an alarm sigml to give the engine man notice that his train is approaching a block signal and then, in the event of the enginemans disregarding this alarm signal to apply the brakes automatically and bring the train to a predetermined speed or to complete rest, or for the limitation of the trains speed by automatically applying the brakes in successive stages at predetermined successive points on the track lying within a given braking stretch and thus to cause the train to be brought to rest at a point just to the rear of the entrance to an occupied block, irrespective of the speed at which the train is travelling and provided only the block remains occupied as long as the train is passing this braking stretch, whereas in the event of the blocks becoming free during the trains passing the braking stretch the actuating devices are rendered ineffective, thus avoiding an unnecessary braking or stopping of the train.

My invention relates to a controllingapparatus which, makes particularly use of the electrical properties of the Well-known photo-electric cells under various light intensities, such as those consisting essentially of the metal selenium. These photo-electric cells have the peculiar characteristic of varying their electrical resistance under various light intensities. Of these properties I make use and-l apply them to the improvements hereinafter more fully set forth, presenting for this object an apparatus which- Will accomplish the purpose with the certainty and reliability needed in practical "railroad service.

Another object ofmy invention is to provide means for the limitation of the trains speed, if a predetermined speed is exceeded over particular parts of the track, such as when passing bridges, curves or the like.

The salient principles of my invention consist in the fact that I provide in combination a source of light placed on the vehicle or 10- comotive, a light sensitive element arranged on the locomotive in proximity to that source of light, and a reflecting member or mirror arranged fixedly on the track adjacent to a block signal and serving as an actuating means for causing the establishment of a signaling or controlling action on the locomotive. This reflecting mirror represents the main feature of my invention and is of a novel and most efficient type to fulfill the requirements of the system in question. It is a so-called triple mirror and consists essentially of three reflecting planes arranged rectangularly with respect to each other. Such a triple mirror has the property of reflecting incoming light rays parallel to their incoming direction or in other ways to reflect incoming light rays into themselves, whatever their incoming direction may be. If one of the three planes is not at right angles to each ofthe other ones, incoming light rays are not reflected in a parallel direction, but the outgoing or reflected rays form a constant angle with the incoming rays, this angle depending on the angle the planes vary from their rectangular position with respect to each other. By the use of a triple mirror as explained I ensure,even with considerable speeds of the train, that the light sensitive cell on the 10- comotive is influenced a sufiiciently long period of time by the light rays radiated by the source of light on the locomotive to the reflecting mirror on the track and thrown back again by the same to the locomotive to strike the light sensitive element whatever their incoming direction may be.

My invention, as just outlined, presents essential advantages in that special sources of light for the transmission of signals are dispensed with, it being only necessary to arrange one source of light on the locomotive. Therefore, the operating costs and costs of surveillance are kept low and existting signal lights on the track are not hampered by the addition of new ones.

According to another feature of my invention I provide light rays of different properties for producing the aforementioned selective actions for certain purposes, e. g., I may use light rays of different colors. When using light rays -'of different color or other different properties (as differently polarized lights) I may get rid of other disturbing sources of light and atmospheric influences, such as very dense fogs. For instance, I may use, a sort of light not contained in ordinary light, i. e., normal day light, or white light of an artificial light source, such as ultra-red or ultra-violet light or light polarized according to a distinct plane of polarization. I may, for this object provide also other rays having a physical affinity for light rays, such as electric rays, X-rays making use of suitable reflecting materials, but my invention as specified or practical use in railroad service is primarily intended to the application of visual light rays. When producing selective actions by lights of different properties, the light influenced receiver is to be given corresponding optically selective properties, e. g, by arranging light filters (colored glasses) when working with differently colored light rays. I may apply the selective properties to the reflected rays when producing different actions, e. g., in placing filter glasses of different color in front of each one of the mirrors arranged on the track and using a corresponding number of light sensitive elements each covered by a glass or filter of different color corresponding to one of those placed in front of the mirrors. Each light sensitive element is included in an individual electrical circuit of a relay which will be energized as long as the light rays influence the light sensitive element and deenergized when such influence ceases, and thus produce a distinct selective action, which only takes place in the event that the locomotive is passing a signal mirror having a filter corresponding to that of its corresponding light sensitive element. The effect produced will be the same when employing a polarizing device, such as a Nicols prism, placed in front of each mirror and a corresponding analyzing device placed in front of each of the corresponding light sensitive elements. Each polarizing device produces light polarized according to a distinct plane of polarization, which light rays may only pass thru the analyser placed in front of its individual light sensitive cell and adapted to let pass only light having a distinct polarization.

In order to obtain the aforesaid selective actions at different points on the track I may employ triple mirrors at the different points, each having another angle of inclination of one of its planes with respect to the other ones, which are placed at right angles with respect to each other, or, as, I may call it, by using trlple mirrors having different orientation. Thus, each one of said mirrors has the property of reflecting incoming light waves irrespective of their incoming direction at a constant angle to this incoming direction, this angle being dependent only on the orientation of each individual mirror. Then, by positioning the single light sensitive cells pertaining to each one of the mirrors in a position with respect to each other and to the light source the effect will be obtained that each cell will be struck only by rays coming from a distinct direction which may be adjusted as being that corresponding to the orientation of an individual mirror.

According to another feature of my invention I may render the light rays selective by varying their intensity periodically or modulating them in accordance with a sine variation such as when employing an A. C. supplying an incandescent lamp and by using receiving devices responsive to such particular periodicity.

In order that my invention will be more fully understood the following detailed description may be taken, reference being had to the accompanying drawings in which:

Figure 1 is a schematic view illustrating the salient principles of the working details of my invention.

Figure 2 is a vertical cross line along the section my according to Figure 1.

Figure 3 represents schematically the structure of a triple mirror such as is used in the apparatus of my invention.

Figures 4-6 are illustrative of an arrangement for successively reducing the trains Speed, getting selective actions by employinglight of different colors.

Referring more particularly to Figure 1 of the drawing the numeral 1 designates the track and 2 the locomotive to which is rigidly secured a box 3 containing an incandescent lamp 4 as a source of light. At the top of the box 3 is secured a lens 5 projecting a beam of light to a triple mirror 6 secured rigidly on a bracket 7 which is supported by a pole 8 erected at the side of the track adjacent to a blocked section. A protecting cover 9 is placed in front of the mirror to prevent exterior disturbances from reaching the mirror planes.

At the side of the box 3 in proximity to the lamp 4 or the lens 5 is placed a light sensitive element 10. When the locomotive is passing the signal pole 8, light; rays radiated by the incandescent lamp 4 are reflected in the same direction as that in which they reach the mirror 6 provided the mirror planes are arranged at right angles with respect to each other, and thereby strike the lightsensitive element 10 which by the variat'ion of its electrical resistance operates a relay of a local circuit, which relay introduces the execution of the action required,

e. g., sound an alarm bell or actuates the brakes, in a manner commonly known in the art and not further described as being withoutthe scope of the invention.

In Figure 2 which is a vertical cross section along the line :z: i of Figure 1, the nun'ieral l0 designates the light sensitive cell at two different positions A and B respectively of the locomotive with respect to the fixedly arranged mirror 6, it being assumed that the train is moving from A to B. The incandescent lamp 4 and the light sensitive cell 10 placed in close proximity to itare at the beginning of the influencing period supposed to be at point A, e. g. 0.5 111. in advance of the mirror 6 which has been fully opened simultaneously with the setting of the rail block signal into the danger position. The cone of light rays radiated by the incandescent lamp may have an opening angle ,8 and its axis is at an angle of 0: degrees with respect to the direction of the movement of the tram, which angle in the case ilhistrated is of 90. In the position A the cone of light rays entirely covers the mirror 6. If the' locomotive is moving by, the mirror 6 will continually be struck by the light ray cone so that even in the position designated by B, i. e., 0.5 m. beyond the mirror, the latter-is yet covered entirely by the cone of light. The duration of influencing the light sensitive cell, therefore, in this instance, is along a stretch of 1 m. corresponding to 1/10 see. when assuming the speed of the train to be r of 36 km. per hour.

Figure 3 shows schematically the structure of the reflecting mirror as employed in the arrangementof my invention. 11, 12 and 13 are three reflecting planes, e. g., three ordinary mirror planes arranged as the planes of a three dimensional Cartesian rectangular coordinate system having axes w, y, 2. This mirror designated a triple mirror has the peculiar property of reflecting a beam 14 of light falling on onc-of its planes 13, e. g., in a parallel direction as shown by the numeral 15 in the drawing, whichmay readily be ascertained by a theoretical consideration.

Referring now more particularly to Figures 1-6 of the drawings, which are illustrative of a system for producing selective actions at different points on the track, four reflecting mirrors 16, 17, 18 and 19 are arranged at successive distances along the track, e. g., of 150 m. from each other. A designates an alarm stop signal and M the main block signal their distance being of 700 m., and it is required, in the event of the block being occupied that the train be brought to rest just to the rear of the block signal irrespective of the speed with which it is travelling. The mirror 16 is placed at 250 m. distance beyond the alarm stop signal A and 450 n1. in advance of the. main block signal M, the second mirror 17 is placed 300 m., the third mirror 18 is at 150 m. distance from the main block signal and the fourth mirror 19 is arranged in close proximity to the main block signal M. The mirrors are provided with glass filters placed in front of them each being of different color, e. g., mirror 16 having a blue, mirror 17 a green, mirror 18 a yellow and mirror 19 having a red filter placed in front of it so that only light of distinct color will be reflected by each one of the respective mirrors, supposing the incandescent lamp on the locomotive is radiating ordinary White light. Upon the locomotive in close proximity to the incandescent lamp, four individual receivers (light sensitive elements) are placed having each a light filter placed front of it of a color corresponding to one of said light filters of the mirrors, so that each receiver will be influenced by light of a special color only or as may readily be seen, by a distinct one of the mirrors 1619 only. A local current may then be established thru the receiver which energizes a relay, which relay puts into operation the brakes of the train. By the combination with this system of a mechanical speed responsive device (tachometer), such as a centrifugal speed device illustrated by Figure 5, a successive limitation of the trains speed until complete rest at the rear of point 19 just at the entrance of the'occupied block may be ensured. According to Fig ure 5 the numeral 20 designates a centrifugal speed device driven from an axle of the loco-- motive and having an indicating hand 21 of electrically conducting material which moves upon a disc having four contact segments 22-25 separated by insulating segments 8437. Each of the contact segments pole 22-25 is conductively connected to one of a receiver (light sensitive element) 26, 27, 28, 29, respectively, the other poles of the receivers being connected to one terminal of a local battery 30. The other battery terminal is connected in series with the winding 31 of a relay 32 and with the hand 21 of the centrifugal speed device 20. The armature 33 of the relay 32 controls an electricalcircuit operating the brake of the train in a manner well known in the art. The contact segments of the disc 20 are so 23 as the train-"has a speed less than 25 km. per hour, on segment 24 as long as the speed is between 50 and 25 km. p. h., and on segment 25 as long as the speed is between 50 and km. p. 11. and on segment 22 when the speed exceeds 70' km. p. h., corresponddesigned that the hand 21 moves on segment- Figure 4, are provided with filters of different colors as indicated in the drawings, and as the receivers 2629 are provided also with filters each corresponding to a filter of one of said mirrors, the eflect is obtained, that, if the train arrives at point 16, traveling at a speed higher than 7 0 km. p. 11., hand 21 is in contact with segment 22 and the receiver 26 is influenced by the mirror at 16, both having blue colored filters, so that the current of the relay is closed over the receiver 26, contact segment 22, hand 21 winding 31 and battery 30. .Hence the ar-- mature 33 of the relay 32 is attracted thus closing a local circuit operating the brakes of the train, whose speed will be diminished and the speed indicating hand 21 will move back until it reaches the insulating segment 84 between segment 22 and 25 and thus interrupt the current flow just mentioned and stop the action of the brakes. The same operations take place at points 17, 18 and 19 where maximum speeds of 50 km. p. h., 25 km. p. h. and 0 km. 1). h. respectively corresponding togreen, yellow and red colors of the respective filters are assumed. Fig. 6 in which the numerals similar to that of Figure 5 refer to equivalent elements shows a modification of the device according to Figure 5 in that four coaxially arranged contact segments 38, 39, 40 and 41 of different lengths are employed over which the hand 21 moves. The effect is the same as obtained in Figure 5, the hand putting successively into the relay circuit the receivers 26, 27, 28,29 in accordance with the respective predetermined speed ranges of the train. It is thus ensured that the speed of each train is reduced earlier or later according to its initial value and that the train is thus stopped with certainty just at the rear of the main block signal M, irrespective the speed with which it is travelling. By varying the length of the contacting sectors 22--25 an adjustment for different categories of trains such as express trains, goods trains etc. may be carried out. A further improvement may be incorporated with the arrangement just explained in that the circuits closed by the contacting segments of the contact disc and consequently the relay are rendered ineffective in case the en ine driver has operated the brakes himsel There may be added also to the system a mirror arranged a certain distance in advance of the alarm block signal for the purpose of operating an optical or acoustic alarm, giving the engine driver notice that his train is approaching a rail block signal. Instead of completely stopping the train, the apparatus just described may serve to reduce its speed to a certain maximum speed to be maintained by the train under certain conditions.

To obviate the disturbing influence caused by strange light, i. e., light not reflected by the mirrors, I may employ light polarized with respect to a special plane of polarization by placing in front of the mirrors a prism or polarizer adapted to produce light polarized according to one distinct plane of polarization. At thereceiving end I employ a double receiver. This double receiver has two light sensitive cells, in front of each of which is placed a prism or analyser having planes of polarization at right angles to each other and which are transparent only to light rays polarized according to their particular plane of polarization, respectively. The plane of polarization of one of these analysers may be so chosen as to coincide with the plane of polarization of the light reflected by the signal mirror. This latter light will, therefore, influence only one of the light sensitive elements of the double receiver, whereas ordinary light being polarized according to any plane will influence both light sensitive elements of the double receivers. The action on the second cell of the receiver is used to stop the action of the first one, 0. g.. by operating a relay which opens the current circuit of the lirst cell, thus rendering it in effective. Therefore, ordinary sources of light. as the suns rays. incandescent lamps and the like will not influence the receiver. However, for practical purposes the arrangement just described of using polarzicd light may be dispensed with, it being .sufiicient, as represented in Figure 1, to have the signal rays starting in a vertical direction and to protect the signal mirror by acover, to avoid the influence of foreign sources of light.

I do not desire to limit myself to the particular construction and arrangement of parts shown and described, but aim in the appended claims to cover all modifications which are within the spirit and scope of my invention:

\Vhat I claim as new and desire to secure by Letters Patent of the United States is:

1. In an automatic train control system of the character described, the combination of electro-mechanical brake control means on.

a locomotive including a light-influenced element and actuable for a brake "controlling .action only when said element is influenced by the action of light, a light source arranged on the locomotive, and a wayside signalling device comprising a light-reflecting member having three reflecting surfaces angularly related with respect to each other so as to reflect light rays projected from said light source at a constant angle with re- .spect to the direction of projection against said light-influenced element.

2. In an automatic train control system of the character described, the combination of electro-mechanical brake control means on a 1 locomotive including a light-influenced eleinfluenced by the ment and actuable for a brake controlling action only when said element is influenced by the action of light, a light source arranged on the locomotive, and a wayside signalling device comprising a light reflecting member having three reflecting planes positioned at right angles with respect to each other and-adapted to reflect light rays projected from said light source in a direction parallel to the direction of projection agalnst said light-influenced element.

3. In an automatic train control system of the character described, the combination of electro-mechanical brake control means on a locomotiveincluding a plurality of lightinfluenced elements and actuatable only when one or the other of said elements is influenced by on the locomotive, a plurality of way-side light-reflecting members arranged at different distances from a predetermined track point and each having three reflecting planes so angularly related as to reflect light rays projected from said source at a constant angle, and means for selectively rendering operative one or the other of said reflecting members to coact with one or the other of said light-influenced elements in accord-- ance with different degrees of speed of the train and its distance from said predetermined track point. j

4. In an automatic train control system of the character described, the combination of electromechanical brake control means on a locomotive including a plurality of light influenced elements and actuatable when one or the other of said elements is action of light, a light source on the locomotive, a plurality of wayside light-reflecting members arranged at different distances from a redetermined track point and each having three reflecting planes so angularly related with respect to each other as to reflect light rays projected from said light source at a constant angle, light filters associated with said reflecting members and said light-influenced elements for selectively rendering operative one or the other of said reflect'ng members for 00- action with one of said light-influenced elements, and means for selectively rendering 4 operativesaid light-influenced elements in accordance with different degrees of speed of thetrain and its distance from said predetermined track point.

5. In an automatic train control system of the character described, the combination of electro-mechanical brake control means on a locomotive including a plurality of li ht-influenced elements and actuatable w on one or the other of said elements is influenced by the action of light, a light Source on the locomotive,

the action of light, a light-source ent predetermined a plurality of wayside light-reflecting members arranged at different distances from a predetermined track point and each having t ree reflecting planes so angularly related with respect to each other as to reflect light rays projected from said light source at a constant angle, light filters associated with said reflecting members and said light-influenced elements for selectively rendering operative one or of electro-mechanical control means on a locomotive including a influenced control elements, a llght source on the locomotive, a plurality of wayside light reflecting members arranged at differdistances from a redetermined track point, each of said re 'ecting members having three reflecting surfaces arranged at right angles to each other and adapted to reflect incoming light rays projected from said light source parallel with the direction of projection against one or the other of said light infiuenced elements, and means for selectively connecting said light influenced elements with the train conplurality 1 of lighttrol means in accordance with dilferent degrees of the speed of the train and its distance from said predetermined track point.

7. In an automatic train control system,

brake control means on a locomotive includlng a photosensltlve control element, alight source on the locomotive, and a wayslde signal comprising a system of reflectors for intercepting light from the light source and reflecting the same at a constant angle against said photosensitive control element.

8. In an automatic train control system, brake control means on a locomotive including a plurality of photosensitive control elements, a light source plurality of wayside light reflectors arranged at different distances from a rede-' termined track point and each inclu in a system of three surfaces operative'to re ect light rays projected from said source at a constant angle, and means for selectively rendering one or the other of said reflectors and one or the other of said photosensitive control elements operative for governing the brake control means accordin to the speed of the train and its distance from said predetermined track point.

9. Controlling means for a power driven.

structure arranged totravel in a constrained path along a, permanent way, comprising on the locomotive, a-

means for producing directed beams of light, members for effecting a diversity of modes a plurality of cells responsive thereto, inof response of said cells at the various retercepting members efi'ective at various presponsive positions to thereby control move- 10 selected positions along the permanent way ments of the structure.

5 for causing the activation of the various In testimony whereof I have afiixed my cells to be varied according to the position signature.

of the moving structure, and color-selective WOLFGANG BASELER. 

